The invention relates generally to an apparatus for winding a plurality of multi-filament strands or bundles into packages which maintains individual strand spacing and identity and more specifically to an apparatus for producing packages of a plurality of multi-filament strands having high strand integrity and distribution uniformity which results in stable package edges and facilitates snag and loop free removal of the strands from the package during subsequent operations.
Continuous filament materials such as glass fibers are commonly utilized in numerous and diverse products as a fibrous reinforcing material. Such material generally consist of a plurality of fiber bundles or strands which are in turn composed of a plurality of individual filaments. Such individual filaments are formed by a multi-orifice bushing, attenuated, sized, gathered into strands or bundles and then directly wound on a rotating collet into a hollow cylindrical package. Subsequently, one, and generally a plurality, of the packages provide pluralities of strands or bundles of filaments which are then formed into roving or utilized in other fabrication processes.
Many manufacturing and use constraints have been placed upon the packages so prepared. First of all, because the package must undergo certain and often extended handling, it is desirable that the corners and ends of the package be uniform and tightly wound in order to minimize the probability of damage to the package. Damage to the package manifests itself in broken filaments and strands. When the package is being unwound, filament and strand breaks significantly interfere with manufacturing processes and can significantly lower production throughput.
A second, related and more significant difficulty relates to the uniform withdrawal of strands or bundles from the package. Since typical fiber production may produce between ten and twenty strands or bundles of filaments which are aligned to form a sheet or array which is wound into the package, it is necessary that the material be removed in the same configuration. However, due to winding inaccuracies, the individual strands may unwind from the package in unequal lengths, generating loops, slack and other undesirable features in the array of strands. If the length differences become great enough, snarling of the strands can occur and strand removal from a package may necessarily be stopped to even out the strands and then restarted.
The apparatus for preparing such packages has been the object of much attention and development. Current technology in this field is relatively sophisticated. For example, U.S. Pat. No. 3,365,145 discloses an apparatus having a traversing guide and projecting pins which engage the band of strands winding onto the collet, ensuring that the band maintains uniform end positions resulting in a relatively straight edged package. A similar device utilizing guide pins is disclosed in U.S. Pat. No. 3,371,877. The apparatus disclosed therein includes a comb-like traversing guide. Each slot of the comb receives a single strand or bundle of filaments. Pins at each end of the guide comb engage the bundles and are intended to provide a straight edged package.
In U.S. Pat. No. 4,322,041, a traversing guide member is disposed proximate the package. The guide receives the strands in a V-shaped slot, the strands contact and are guided by one of the two sides of the slot depending upon which way the guide is traversing. The strand guide is maintained at a constant spacing from the outer surface of the wound package by means which contact the collet and the package forming thereupon.
U.S. Pat. No. 4,538,773 teaches another apparatus for collecting strands of filaments in which an oscillating guide includes a V-shaped slot and the oscillating guide traverses between a pair of pins. The pins are oriented generally parallel to the more adjacent sidewall of the V-shaped slot. Improved uniformity of package edges is also claimed for this apparatus.
From a review of the foregoing patent literature directed to package winding apparatus, it is apparent that improvements in this art are not only desirable but possible.